Add Makefile with targets for common actions

Makefile

@@ -0,0 +1,29 @@
+TEST_SITE := tests/data/sites/main
+OUTPUT    := $(TEST_SITE)/output
+
+.PHONY: build build-drafts check test coverage clean serve
+
+build:
+	OSSG_TYPECHECKED="1" ossg --site $(TEST_SITE) -v build
+
+build-drafts:
+	OSSG_TYPECHECKED="1" ossg --site $(TEST_SITE) -v build --drafts
+
+check:
+	mypy -p omicron.ssg
+	black --check omicron tests/unit tests/e2e
+
+test:
+	pytest
+
+coverage:
+	coverage run -m pytest tests/unit
+	coverage report
+	coverage html
+	@echo "file://$(CURDIR)/htmlcov/index.html"
+
+clean:
+	ossg --site $(TEST_SITE) clean
+
+serve:
+	python -m http.server --bind 127.0.0.1 --directory $(OUTPUT)